Monday, July 07, 2008

Climate Change Might Be Turning Us Into Chesapeake Bay

Fifty of years of data from weekly trawls by fisheries biologists at the University of Rhode Island seem to indicate that our southern New England estuaries are slowly turning into mid-Atlantic estuaries – Narragansett Bay is becoming more like Chesapeake Bay.

Science Daily reported the other day that the URI scientists have documented a clear, long-term shift in the species that inhabit not just Narragansett Bay but the nearby waters of the Atlantic as well.

It’s the same kind of shift the Connecticut DEP biologists have seen over 25 years in Long Island Sound. And just as in the Sound, the URI biologists attribute the change to global warming. It was discussed at the Long Island Sound Citizen Summits in 2006 (which I wrote about here) and again in 2008 (read it here).

Here are some excerpts from Science Daily:

According to Jeremy Collie, professor of oceanography at the University of Rhode Island's Graduate School of Oceanography, the fish community has shifted progressively from vertebrate species (fish) to invertebrates (lobsters, crabs and squid) and from benthic or demersal species -- those that feed on the bottom -- to pelagic species that feed higher in the water column. In addition, smaller, warm-water species have increased while larger, cool-water species have declined.

"This is a pretty dramatic change, and it's a pattern that is being seen in other ecosystems, including offshore on Georges Bank and other continental shelf ecosystems, but we're in the relatively unique position of being able to document it. These patterns are likely being seen in estuaries around the world, but nowhere else has similar data," said Collie. …

Collie said that while most of the changes occurred slowly, an abrupt change appeared to take place in 1980 and 1981 when benthic species like winter flounder and silver hake declined and pelagic species including butterfish and bluefish increased. …

… he believes that climate is "the dominant signal." Sea surface temperature in the area of the trawls has increased by 2 degrees Centigrade since 1959, and the preferred temperature of the fish caught in the trawls has also increased by 2 degrees C.

"That seems to be direct evidence of global warming," he said. "It's hard to explain any other way." …

What do these changes mean for the future of Narragansett Bay?

"Our overall prediction is that Narragansett Bay is soon going to resemble estuaries to the south of us -- Delaware Bay, Chesapeake Bay -- so we'll experience what they are experiencing now," Collie said. "It will continue to get warmer and attract more southern species, such as blue crabs. Species that couldn't complete their life cycle here before may be able to do that now."

I have no idea if becoming more like Chesapeake Bay is a good thing or a bad thing. I do remember, though, that I've been told more than once that people don't swim in the Chesapeake because there are too many jellyfish. Coincidentally there's a talk tomorrow afternoon at Yale by Dr. Richard Brodeur, of NOAA's NorthwestFisheriesScienceCenter, on "Climate Change and the Role of Jellyfish in Coastal Ecosystems."

It’s at 1 p.m. in room 102 of the KlineBiologyTower, 219 Prospect Street, New Haven.

I was a little confused by some of this, as as the lobster numbers are declining radically since the 1970's but supposedly such benthic creatures are coming back.

Then I was mystified, since the size of the striper (striped bass, rockfish) is getting larger, although perhaps not a commercial fish anymore.

Perhaps this is specific to Narragansett Bay, which has had a host of environmental problems including massive sewage inputs, hypoxia, declining sea grasses, and reduced shad run. A bunch of that seems man-made. Sure, climate change is happening but it was not so convincing as I've seen explained elsewhere (e.g., LIS temperature anomalies).

So I guess I have to wait for the real article, as this synopsis wasn't written very clearly - not you Tom but the one in the link.

The kids and I had a refreshing swim in the Sound in Riverhead, Long Island yesterday. Quite cold! Much colder than the chlorinated swims now widely available hereabout. So many people seem to have pools now or are spending the day at the water park that we practically had the beach to ourselves on a balmy Monday, July 7. Eery...

By Tom Andersen

About Sphere & Tom Andersen

This is a blog about environmental issues in the New York area in general and Long Island Sound in particular. I'm the author of
"This Fine Piece of Water: An Environmental History of Long Island Sound," which came out in 2002. I wrote about the environment and other issues during almost two decades as a newspaper reporter.

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